1,2,3,4-Butanetetracarboxylic acid, tetrakis(2,2,6,6-tetramethyl-4-piperidinyl) ester 105643-87-6 141257-26-3 194352-45-9 64022-61-3 EINECS 264-611-6 Tetrakis(2,2,6,6-tetramethyl-4-piperidyl) butane-1,2,3,4-tetracarboxylate